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The login page at /login is a Blazor Server component that renders a credential form, validates input with Data Annotations, delegates authentication to the AuthenticateUser use case, and navigates to /admin on success. The entire flow — validation, use-case call, navigation or error display — runs inside a single HandleLogin method wired to the form’s OnValidSubmit event.

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Form model

The component defines a nested LoginModel class that carries the form fields and their validation rules:
Login.razor (@code)
public class LoginModel
{
    [Required, EmailAddress]
    public string Email { get; set; } = string.Empty;

    [Required]
    public string Password { get; set; } = string.Empty;
}
[Required] ensures neither field can be submitted empty. [EmailAddress] enforces a valid email format on the Email field (for example, user@example.com). Both attributes are standard System.ComponentModel.DataAnnotations decorators and are evaluated automatically by the <DataAnnotationsValidator> component inside the form — the form will not call HandleLogin until all validations pass. The model instance is bound to the form via [SupplyParameterFromForm], which tells Blazor to populate the model from the HTTP form data on a static SSR POST:
Login.razor (@code)
[SupplyParameterFromForm]
private LoginModel model { get; set; } = new LoginModel();
private string error = string.Empty;

​
Authentication logic

When the form passes validation, Blazor invokes HandleLogin:
Login.razor (@code)
private async Task HandleLogin()
{
    error = string.Empty;

    AuthResult? result = await AuthenticateUserUseCase.ExecuteAsync(model.Email, model.Password);

    if (result.Success)
    {
        NavigationManager.NavigateTo("/admin");
    }
    else
    {
        error = "Usuario o contraseña inválidos";
    }
}
The flow proceeds in three steps:
1

Clear previous errors

error is reset to an empty string so stale error messages from a previous attempt are not shown.
2

Call AuthenticateUser

AuthenticateUserUseCase.ExecuteAsync(email, password) looks up the user by email, verifies the password hash using IPasswordHasher, and — if credentials are valid — calls ISessionManager.SignInAsync() to write an authentication cookie to the response. It returns an AuthResult DTO with a Success boolean.
3

Navigate or display error

If result.Success is true, NavigationManager.NavigateTo("/admin") performs a client-side navigation to the admin dashboard. If false, the error string is set to "Usuario o contraseña inválidos" and re-rendered below the form.

​
Form rendering

The Razor markup renders the form using Blazor’s <EditForm> component:
Login.razor
<EditForm Model="model" OnValidSubmit="HandleLogin" FormName="login">
    <DataAnnotationsValidator />
    <ValidationSummary />
    <div class="form-group">
        <label>Email</label>
        <InputText class="form-control" @bind-Value="model.Email" placeholder="Email" />
    </div>
    <div class="form-group">
        <label>Password</label>
        <InputText class="form-control" type="password" @bind-Value="model.Password" />
    </div>
    <button>Entrar</button>
</EditForm>
Key elements:
ElementPurpose
<EditForm Model="model">Binds the form to the LoginModel instance and manages its EditContext
OnValidSubmit="HandleLogin"Fires HandleLogin only when all validation rules pass
FormName="login"Gives the form a stable name for Blazor’s static SSR form handling
<DataAnnotationsValidator />Wires the EditContext to Data Annotations so [Required] and [EmailAddress] are enforced
<ValidationSummary />Renders a consolidated list of all validation messages above the fields
@bind-Value="model.Email"Two-way binds the <InputText> to the Email property
type="password" on the password <InputText>Masks the input in the browser
Error messages from a failed login attempt are displayed below the form:
Login.razor (error display)
@if (!string.IsNullOrEmpty(error))
{
    <p>@error</p>
}

​
Injected dependencies

Login.razor declares two @inject directives at the top of the file:
Login.razor
@inject NavigationManager NavigationManager
@inject AuthenticateUser AuthenticateUserUseCase
Both services are registered in Program.cs:
  • AuthenticateUser — registered as AddScoped<AuthenticateUser>(). It encapsulates the credential validation and session creation logic, keeping the page component free of infrastructure concerns.
  • NavigationManager — a built-in Blazor service, always available without explicit registration, used to trigger the post-login redirect.
This page uses Blazor’s built-in form handling (EditForm, OnValidSubmit). The HandleLogin method is only invoked when all Data Annotations validations pass — if Email is blank or malformed, or Password is empty, Blazor blocks submission and displays the validation messages via <ValidationSummary /> without ever calling HandleLogin.
To add a Remember Me feature, add a RememberMe boolean property to LoginModel and bind it to a checkbox in the form. The LoginRequest DTO already defines a RememberMe field (bool RememberMe = false), but the wiring is not yet complete: AuthenticateUser.ExecuteAsync currently accepts only (string email, string password) and ISessionManager.SignInAsync accepts only a User. To complete the feature you would need to: (1) add a rememberMe parameter to AuthenticateUser.ExecuteAsync, (2) add it to ISessionManager.SignInAsync, and (3) update CookieSessionManager.SignInAsync to set IsPersistent = rememberMe on the AuthenticationProperties passed to HttpContext.SignInAsync.

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